x86, pmem: use memcpy_mcsafe() for memcpy_from_pmem()

Update the definition of memcpy_from_pmem() to return 0 or a negative
error code.  Implement x86/arch_memcpy_from_pmem() with memcpy_mcsafe().

Cc: Borislav Petkov <bp@alien8.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
index bf8b35d..fbc5e92 100644 (file)
--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -47,6 +47,15 @@ static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src,
                BUG();
 }
 
+static inline int arch_memcpy_from_pmem(void *dst, const void __pmem *src,
+               size_t n)
+{
+       if (static_cpu_has(X86_FEATURE_MCE_RECOVERY))
+               return memcpy_mcsafe(dst, (void __force *) src, n);
+       memcpy(dst, (void __force *) src, n);
+       return 0;
+}
+
 /**
  * arch_wmb_pmem - synchronize writes to persistent memory
  *

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index ca5721c..cc31c6f 100644 (file)
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -99,7 +99,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
                if (unlikely(bad_pmem))
                        rc = -EIO;
                else {
-                       memcpy_from_pmem(mem + off, pmem_addr, len);
+                       rc = memcpy_from_pmem(mem + off, pmem_addr, len);
                        flush_dcache_page(page);
                }
        } else {
@@ -295,7 +295,7 @@ static int pmem_rw_bytes(struct nd_namespace_common *ndns,
 
                if (unlikely(is_bad_pmem(&pmem->bb, offset / 512, sz_align)))
                        return -EIO;
-               memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
+               return memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
        } else {
                memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
                wmb_pmem();

diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index 3ec5309..ac6d872 100644 (file)
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -42,6 +42,13 @@ static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src,
        BUG();
 }
 
+static inline int arch_memcpy_from_pmem(void *dst, const void __pmem *src,
+               size_t n)
+{
+       BUG();
+       return -EFAULT;
+}
+
 static inline size_t arch_copy_from_iter_pmem(void __pmem *addr, size_t bytes,
                struct iov_iter *i)
 {
@@ -66,14 +73,17 @@ static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
 #endif
 
 /*
- * Architectures that define ARCH_HAS_PMEM_API must provide
- * implementations for arch_memcpy_to_pmem(), arch_wmb_pmem(),
- * arch_copy_from_iter_pmem(), arch_clear_pmem(), arch_wb_cache_pmem()
- * and arch_has_wmb_pmem().
+ * memcpy_from_pmem - read from persistent memory with error handling
+ * @dst: destination buffer
+ * @src: source buffer
+ * @size: transfer length
+ *
+ * Returns 0 on success negative error code on failure.
  */
-static inline void memcpy_from_pmem(void *dst, void __pmem const *src, size_t size)
+static inline int memcpy_from_pmem(void *dst, void __pmem const *src,
+               size_t size)
 {
-       memcpy(dst, (void __force const *) src, size);
+       return arch_memcpy_from_pmem(dst, src, size);
 }
 
 static inline bool arch_has_pmem_api(void)